Final answer:
Excessive squeezing around a capillary puncture site can lead to dilution of the sample with tissue fluid by forcing interstitial fluid to mix with blood, potentially altering test results.
Step-by-step explanation:
Excessive squeezing around a capillary puncture site can dilute the blood sample with tissue fluid. This is due to the pressure applied which forces interstitial fluid, the fluid that surrounds the cells, to mix with the blood. This contamination of the blood sample with tissue fluid can affect the accuracy of test results, as the concentration of blood components may appear lower than they actually are.
Injury to blood vessels, like those experienced during a capillary puncture, involves the leakage of blood and its components (e.g., erythrocytes, white blood cells) out of the breaks. Additionally, Figure 26.9 shows that edema, the accumulation of excess fluid in the tissues, can occur due to allergic reactions or other factors that cause capillaries to leak. This is analogous to what happens when squeezing induces additional interstitial fluid into the sample.